Dual P-MAG Reliability in 2017

Flyfish said:

I thought this was a thread about P-Mags.

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You would think so, but the original question of dual p mag reliability seemed to be answered some time ago. This thread has actually thrown out a lot of information for 2 different ignition systems and lays out the benefits and draw backs of both. Almost. The pmags are much easier to install and can be a quick way to get into the EI game. However the CPI is a much more tuneable system from the get go, but it takes quite a bit more work to get installed initially. This thread has actually forced me to do more research on both systems. I do like the tunability with the CPI, but that big clunky controller is probably a deal killer for me. Wish they made a small 2 1/4" that did the same thing, along the lines of the EI commander. Or better yet if garmin would work with one of these companies and build a controller into the g3x system. I'm sure it looks cool in a race car but I feel like it looks too gimmicky for a plane. Either way, this has been an informational thread.

Timberwolf said:

You would think so, but the original question of dual p mag reliability seemed to be answered some time ago. This thread has actually thrown out a lot of information for 2 different ignition systems and lays out the benefits and draw backs of both. Almost. The pmags are much easier to install and can be a quick way to get into the EI game. However the CPI is a much more tuneable system from the get go, but it takes quite a bit more work to get installed initially. This thread has actually forced me to do more research on both systems. I do like the tunability with the CPI, but that big clunky controller is probably a deal killer for me. Wish they made a small 2 1/4" that did the same thing, along the lines of the EI commander. Or better yet if garmin would work with one of these companies and build a controller into the g3x system. I'm sure it looks cool in a race car but I feel like it looks too gimmicky for a plane. Either way, this has been an informational thread.

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Glad it's been informational. The CPI2 under development will have a much smaller footprint than the present setup and the green will be gone. Garmin won't play unless you can show a good case for benefits to them which is totally understandable. They have been approached and there will be provisions to communicate with other devices in the new unit to allow for future upgrades.

Dual P-Mags, 6 years, 650+ hours

A few data points and opinions. I was an early adopter of dual P-mags and have been running them for 6 years and over 600 hours. I had a few teething issues in 2011 during my phase 1 testing that were promptly addressed by P-mag.

At about the 150 hour mark I swapped out my aircraft spark plugs for auto plugs and haven't looked back. The P-mags are dirt simple to time, easy to install and operate as advertised. Company service and support is way above the norm.

I get easy starts, smooth low RPM idle and can easily run my O-360 LOP. I'm not interested in experimenting with timing curves. I'm not saying there isn't a better system out there. It depends upon your mission. If I were to build again, I would make the same selection.

RhinoDrvr said:

I like the idea of the P-MAG?s the best, but have been unable to on find any data on reliability of the new, v40 firmware, latest version of the hardware P-MAG?s. I also think the P-MAG would be the most straightforward install given the LASAR setup I would be removing already has a Manifold Pressure Line etc.

What are your thoughts?

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The real data regarding reliability of newer Pmags using v40 firmware is probably available and could be provided by the manufacture of the product. But based on past practice I seriously doubt they will share that data. Why? I am left to speculate.

Of all the Pmag related threads I've read here, I can't remember a single post where someone from Pmag has participated in the discussion. Maybe I've missed a few?

The question of reliability remains a mystery save for a small population of users who chose to share their experiences.

I will be replacing my Slicks soon and have gone through a simular information seeking exercise.

Enjoy your RV-8.

Captain Avgas said:

Now, if I'm reading this right EMAG have stated that they do not know why Loal's PMAG (V37) lost its timing and they have no reason to believe that V40 would have prevented the timing loss.

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That is it... right there in the Captain Avgas quote. P-mags sometime loose timing (still making sparks, just at the wrong time). This greatly reduces engine power (or it quits).

To get back engine power the pilot has to know what to do... turn off the offending P-mag. Now... who among us wants to have to troubleshoot ignitions in flight under an engine out situation? Thats why we have 2 igintions... right? So one can keep us flying until we are ready to land.


With all other ignitions... if one quits or messes up or whatever, the other keeps you going to an airport. The pilot doesn't need to troubleshoot anything till on the ground. That is HUGE! If your ignition isn't automatically redundant like this, you can change it to be.

No other ignition gets off timing like that.

WAM120RV said:

However that is why we have dual ignition systems, if one malfunctions you go to the other and land ASAP.

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I have dual ignition systems so that if one malfunctions the other will automatically keep the engine running without a hiccup and without my intervention. The concept that one ignition failing might cause the engine to quit until the offending ignition is identified and switched off is absurd and extremely dangerous.

If an engine quits in flight an ignition check is way down the list of things to do. If it occurs at take-off or landing it is highly unlikely that the pilot will even have the opportunity to do an ignition check.

Andrew Anunson said:

To get back engine power the pilot has to know what to do... turn off the offending P-mag. Now... who among us wants to have to troubleshoot ignitions in flight under an engine out situation? Thats why we have 2 igintions... right? So one can keep us flying until we are ready to land.


With all other ignitions... if one quits or messes up or whatever, the other keeps you going to an airport. The pilot doesn't need to troubleshoot anything till on the ground. That is HUGE! If your ignition isn't automatically redundant like this, you can change it to be.

No other ignition gets off timing like that.

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@Captain Avgas@ said:

I have dual ignition systems so that if one malfunctions the other will automatically keep the engine running without a hiccup and without my intervention. The concept that one ignition failing might cause the engine to quit until the offending ignition is identified and switched off is absurd and extremely dangerous.

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So you've never had, nor heard of, a magneto losing its' timing in flight? A quick Google search shows it is far from rare with traditional magnetos indeed occurring 3 times in a 6-week SDR search, so PMag's are nothing new in this regard, yet everyone seems to be up in arms over it? I don't get it...

From a CAsA bulletin on the subject:

Engine roughness or internal vibration is also frequently linked to incorrect magneto-to-engine timing which can occur during operation, despite the timing being correct at installation.
There has been an increase in SDR reports to CASA describing advances in timing in between periodic inspection periods in 4300 and 6300 series slick magnetos.

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Personally, I have dual ignitions (Dual PMag's as it happens) so that if one fails, however it happens, I can get to an airport. Cycling the magneto switch is one of the 'rough-running' or failure checklist actions for most spam-can's I've flown for precisely this reason...

N941WR said:

The P-mags are great ignitions and way ahead of magnetos. Do they extract maximum performance out of an engine, no; however, neither does the ignition in your car or truck.

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This is completely incorrect. Auto manufacturers have complete control of their ignition maps and spend 1000's of hours on the dyno optimizing fuel flow (i.e. mixture) and ignition timing. It is also done in harmony with other engine variables, such as temps. Granted, they also factor in reliability and emissions. However, they are highly optimized. They sell cars, in part, based upon HP claims. Trust me, they want as high of a number as they can get.

Timing makes a big impact on performance and even though many here don't want to hear it, it is variable based on many factors, the most profound being mixture. I can't imagine having an EI that cannot be adjusted based upon my mixture setting (ROP vs LOP). It would be like not having a mixture control and just feeding full rich through the flight regime.

I do agree with Bill that if you favor simplicity over performance, the Pmag is a good upgrade option over the mag. However, I would still buy the CPI for cost and reliability.

Just to give one example of the benefits of flexibility, I solved my FI hot idle problem by bumping my idle timing to 35.

Larry

Cockpit switches

Ross, with your upcoming CPI2, besides the actual unit you are now designing, what sort of cockpit switches do you recommend for a dual cpi setup? I?m guessing two independent on-off switches for each cpi.

Av8rRob said:

Ross, with your upcoming CPI2, besides the actual unit you are now designing, what sort of cockpit switches do you recommend for a dual cpi setup? I?m guessing two independent on-off switches for each cpi.

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We're trying to eliminate as many external switches on the CPI2 as possible. I can't say at this point until software and testing is closer to completion. That's probably at least a month away.

KRviator said:

So you've never had, nor heard of, a magneto losing its' timing in flight? A quick Google search shows it is far from rare with traditional magnetos indeed occurring 3 times in a 6-week SDR search

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It's not that I'm sceptical, but I think you should state your search criteria and produce the specific case results of your SDR search so that we can ascertain for ourselves if they are valid to the discussion at hand.

rv6ejguy said:

We're trying to eliminate as many external switches on the CPI2 as possible. I can't say at this point until software and testing is closer to completion. That's probably at least a month away.

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Is the newer CPI2 a completely new system, or is it basically an upgraded controller / interface box / display? Is everything firewall forward the same?

maus92 said:

Is the newer CPI2 a completely new system, or is it basically an upgraded controller / interface box / display? Is everything firewall forward the same?

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The PCB, case, display will be all new, all FF components the same as before. I can't talk about some of the other new features planned at this time until we're closer to release.

rv6ejguy said:

The PCB, case, display will be all new, all FF components the same as before. I can't talk about some of the other new features planned at this time until we're closer to release.

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I guess what I'm getting at is there an upgrade path for those who either have installed the current system, or want to install the current version sooner rather than waiting for CPI2?

lr172 said:

This is completely incorrect. Auto manufacturers have complete control of their ignition maps and spend 1000's of hours on the dyno optimizing fuel flow (i.e. mixture) and ignition timing. It is also done in harmony with other engine variables, such as temps. Granted, they also factor in reliability and emissions. However, they are highly optimized. They sell cars, in part, based upon HP claims. Trust me, they want as high of a number as they can get.

Timing makes a big impact on performance and even though many here don't want to hear it, it is variable based on many factors, the most profound being mixture. I can't imagine having an EI that cannot be adjusted based upon my mixture setting (ROP vs LOP). It would be like not having a mixture control and just feeding full rich through the flight regime.

I do agree with Bill that if you favor simplicity over performance, the Pmag is a good upgrade option over the mag. However, I would still buy the CPI for cost and reliability.

Just to give one example of the benefits of flexibility, I solved my FI hot idle problem by bumping my idle timing to 35.

Larry

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The this is completely incorrect.

While it is true that auto manufacturers spend a lot of time developing timing and fueling maps, they do not tune them to extract maximum performance out of your vehicle. They are looking for emissions, reliability, and performance, not necessarily in that order.

When I was doing the auto racing thing, I replaced the ECU and was able to pickup around 5% more torque and HP by tuning the car on a dyno. Of course it was tuned within a breath of its life, something auto makers are loathe to do for obvious reasons.

Another way to look at it is, why are there so many different aftermarket automotive ignitions available, if the auto manufacturer's ignitions are so good?

My biggest issue with multi component systems is the number of connectors that can fail. That is not to mention the additional complexity required by adding extra batteries and alternators to protect against electrical system issues.

Then you still have the problem one LS user had a few years back. He was on short final when his alternator belt broke, ripping out the wires for the crank angle sensor. Instant glider.

In the end, you as the builder have to weigh the risks, both set up and operational, and pick the system that you feel is best for you.

N941WR said:

The this is completely incorrect.

While it is true that auto manufacturers spend a lot of time developing timing and fueling maps, they do not tune them to extract maximum performance out of your vehicle. They are looking for emissions, reliability, and performance, not necessarily in that order.

When I was doing the auto racing thing, I replaced the ECU and was able to pickup around 5% more torque and HP by tuning the car on a dyno. Of course it was tuned within a breath of its life, something auto makers are loathe to do for obvious reasons.

Another way to look at it is, why are there so many different aftermarket automotive ignitions available, if the auto manufacturer's ignitions are so good?

My biggest issue with multi component systems is the number of connectors that can fail. That is not to mention the additional complexity required by adding extra batteries and alternators to protect against electrical system issues.

Then you still have the problem one LS user had a few years back. He was on short final when his alternator belt broke, ripping out the wires for the crank angle sensor. Instant glider.

In the end, you as the builder have to weigh the risks, both set up and operational, and pick the system that you feel is best for you.

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Almost all auto ECUs today use a knock sensor or CPT to advance timing just short of knock at all times for the given fuel octane plus they're taking into account IAT, CLT, MAP and/or MAF, baro etc. to ensure highest BMT at ALL times, whether cruising at part throttle well lean of Stoich or WOT at redline. Since emissions are not measured at WOT/ high rpm in most tests because most car engines don't spend a high percentage of time there, power is paramount under that condition given a reasonable buffer to the edge of detonation which ANY system should have. To suggest otherwise, especially in aircraft, is reckless.

The auto ignitions are orders of magnitude more sophisticated and precise than a Pmag, CPI, LS or anything else in aviation short of Lycoming's IE2 or perhaps the Rockwell system on the Rotax 912iS, which they easily match or exceed.

Any advance in timing will almost certainly affect knock margins and/or emissions. The aftermarket does not need to meet any emissions spec and most say "for off road use only". I don't see many aftermarket ignitions out there for the cars of today outside of Link, Haltech and Motec which are intended mainly for performance / race use at higher boost levels where factory ECUs are not mapped-that longevity/ warranty card again.

No auto OEMs use integrated ignition controllers these days because they found out long ago that long term reliability is compromised by heat and vibration when attached to the engine. The Pmag integrated design was a marketing decision to make installation easier IMO (which it undeniably is), not something based on best engineering practice.

No auto OEMs today use gear driven timing components because it's less precise and more prone to failure. These are reasons why Pmag mandates 100 hour inspections- to make sure the bearings, gears are ok and the electronics have not been overtemped or got wet. Pmag requires blast tubes for cooling as a result of their design decision and they use non-water proof screw type connectors externally. Really, in 2017? You don't see this stuff on modern auto ignitions.

Poor belt maintenance and questionable installation likely caused the LS incident in Australia. Anyway, we can all learn from that and protect crank sensor cables with armor as we recommend. No way a thrown belt will take out our sensor or cables.

The internal generator in the Pmag has caused issues as outlined in their own documentation. http://www.emagair.com/service-notes/ http://www.emagair.com/downloads/

More reliable than a backup battery? Doubtfully. More spinning, vibrating stuff inside to go wrong and cause damage to other critical parts.

Edit, Ross beat me to it.

N941WR said:

...Another way to look at it is, why are there so many different aftermarket automotive ignitions available, if the auto manufacturer's ignitions are so good?....

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Please define an "automotive ignition" so that we have context. Are you discussing something from the 1960's or today? In the 60's you had a true stand alone system: Distributor, amplifier, coil... Today, with the ECU handling many functions, receiving signals from many sensors, its hard to segregate an "ignition system". You can certainly buy aftermarket coils and fat spark plug wires just like in the old days, but a "system"? Please define.

N941WR said:

...My biggest issue with multi component systems is the number of connectors that can fail....

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Please cite actual failure rates "caused" by the use of "Multi component systems". Not what "could" happen, but what actual experience shows "does" happen. Compare that to the engineering challenge of cramming all that stuff into one box to satisfy a marketing niche and see where that gets you? Would you like to compare the history of "magnet misalignment " with Ross' product line? How about "lost timing events"?

I'll grant P-mag the benefit of the doubt that their issues are largely resolved (with frequent, repetitive inspections), but we all know that that has been a long, uphill battle - a battle LARGELY the result of the marketing decision to package it all together - But there is no way you can pound the drum that a "distributed" system is inherently less reliable. No way. To do so flies in the face of logic and absolutely overwhelming evidence to the contrary.

It's time to put that bogey man to rest.

Captain Avgas said:

It's not that I'm sceptical, but I think you should state your search criteria and produce the specific case results of your SDR search so that we can ascertain for ourselves if they are valid to the discussion at hand.

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No problems, Google "Magneto losing timing lycoming" and it is the 2nd from the bottom. Of if you prefer, you can login to the CAsA SDR Portal and search using "Magneto" with no date range yourself. But the initial 3 I found were using Google.
From CAsA's Flight Safety magazine, 01August14-22Sep14:

Lycoming IO540K1A5 Magneto/distributor?magneto unserviceable. SDR 510019711 RH magneto timing found to be approximately 7 degrees advanced. Magneto had 94 hours TSN. P/No: 6350. TSN: 94 hours

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Lycoming IO540K1A5 Magneto/distributor?magneto unserviceable. SDR 510019832 RH magneto timing moved to 4 degrees advanced. Magneto had approximately 50 hours TSN. P/No: 6350. TSN: 50 hours.

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Lycoming O320 Magneto/distributor?magneto unserviceable. SDR 510019703 Magneto losing timing. Timing reset but changed again so magneto replaced. P/No: 4370. TSN: 477 hours.

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However, using the SDR Portal, you find the following using no date range and the search term 'magneto':

The CAsA SDR Portal said:

18 August 2016: On newly overhauled engine after relatively short time in service, magneto timing was advanced by more than 5 degrees. According to Slick SL No. 4300/6300-74-20-001, this amount of timing drift required immediate action. Magneto was therefore removed and returned for warranty claim.

23 December 2015: During a 100 Hourly Inspection, the magneto to engine timing had drifted 4 degrees which was corrected during the 100 Hourly Inspection. On the post 100 Hourly ground run, there was a 200 rpm magneto drop noted on the magneto that had the timing drift (the 200 rpm drop was not there before the timing drift on the pre 100 Hourly ground run). As this magneto drop is beyond limits the magneto was replaced with new, was timed to the engine and a ground run was carried out and found serviceable.

11 November 2015: Left hand engine wouldn't start. The magneto to engine timing was checked (as we have had previous magneto problems) and it was approx. 20 degrees advanced. The magneto was removed and bench checked and was founds approx. 20 degrees advanced with a weak spark below 1,000 rpm.

03 July 2015: LH magneto timing out of adjustment

29 May 2015: LH magneto timing drifting. Investigation found points cam loose. Further investigation found the rotor shaft cam slot had been machined oversize.

05 May 2015: Magneto has a history of the timing setting moving. See attachment for history details.

08 September 2014: RH magneto timing moved to 4 degrees advanced. Magneto had approximately 50 hours TSN.

03 September 2014: LH magneto faulty. Timing was found to be 8 degrees advanced.

02 September 2014: LH magneto faulty. Timing was found to be 10 degrees advanced.

13 August 2014: RH magneto timing found to be approximately 7degrees advanced. Magneto had 94 hours TSN

08 August 2014: Magneto losing timing. Timing reset but changed again so magneto replaced.

20 May 2014: Magneto losing timing settings after a few hours of flight

01 May 2014: Magneto timing advanced 6 degrees from20 degree mark. Found during inspection iaw Slick SB2-08B.

26 April 2014: Magneto losing timing settings after a few hours of flight.

04 April 2014: Magneto losing timing settings after a few hours of flight.

04 April 2014: Magneto unserviceable. Timing advances in use.

25 March 2014: Magneto losing timing settings after a few hours of flight.

13 March 2014: LH magneto timing slowly advances by 5-6 degrees between inspections. Magneto is correctly retimed at each inspection but then slowly advances again.

13 March 2014: RH magneto timing slowly advances by 5-6 degrees between inspections. Magneto is correctly retimed at each inspection but then slowly advances again. See also SDR 510018760 for similar defect on LH magneto.

11 March 2014: Magneto losing timing settings after a few hours of flight.

05 November 2013: On Engine Run-up performance check, right magneto 50 RPM drop. Timing 5 Degrees out.

02 May 2013: RH magneto failed to stay correctly timed. Suspect internal timing slipped due to unknown internal problem. Magneto had been fitted to a newly rebuilt engine.

01 February 2010: Magneto had excessive play in gear shaft bush causing gear to jump teeth and affect timing.

08 August 2008: Magneto internal timing shifted. Timing moved from 20 degrees BTDC to 12 degrees BTDC.

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As you can see, PMags are not alone in the lost-timing issue and I dislike the fact that at least two qualified pilots do not understand basic magneto operation enough to understand they too suffer from timing issues - and they can be a relatively common occurrence too - that can affect engine operation, instead trying to point the finger at PMag as being the only possible culprit in this regard. Now, before anyone suspects I am affiliated with Brad or his company - I have no interaction or association with PMag/EMagAir or any of their employees, other than having two PMag L114's installed on my engine at manufacture by ECI.

These SDR's are a relatively new concept from CAsA, and only capture those that are reported, and only then in Australia, which has a relatively small GA fleet compared to the US, so it is certainly within the realm of possibility an American pilot would expect to experience such a phenomenon and be expected to react accordingly. Commentary here suggests this may not be the case, and if this is indeed true, I would encourage a mag-check to be incorporated as part of your IA's following engine roughness or failure and be practiced as such, at the earliest opportunity. As I said earlier, it was part of the spam-can checklists I was trained under and that is going back close to 20 years, and it is there for a reason.

rv6ejguy said:

Poor belt maintenance and questionable installation likely caused the LS incident in Australia. Anyway, we can all learn from that and protect crank sensor cables with armor as we recommend. No way a thrown belt will take out our sensor or cables.

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I'm on the fence and watching the debate, however the risk of the crank sensor and wires being damaged by alternator belt failure is a key concern for me. Particularly given that I wasn't far from that crash and know the occupant who was very badly burnt. Would like to know more about how the crank sensor and cables can be protected, but didn't find the answer on your website. Can you elaborate here.

Malndi said:

I'm on the fence and watching the debate, however the risk of the crank sensor and wires being damaged by alternator belt failure is a key concern for me. Particularly given that I wasn't far from that crash and know the occupant who was very badly burnt. Would like to know more about how the crank sensor and cables can be protected, but didn't find the answer on your website. Can you elaborate here.

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I've posted photos in other threads on this topic. Our crank sensors and mounts are far more robust than the early LS ones- you can lift the engine up from ours. The mounts also incorporate several threaded holes to attach cable armor to. A number of people posted their solutions here: http://www.vansairforce.com/community/showthread.php?t=152923

The last post here shows a photo of the mount and armor mounting holes: http://www.vansairforce.com/community/showthread.php?t=143608 Go to Page 5, post #44 last page.

I should mention that the early LS crank sensor setup has been superseded by a new design which has the cabling mostly inside the baffle sheet metal.

And another few examples using "Distributor" as the faulty part:

13 March 2014: Magneto distributor block cracked. Suspect due to over torquing of attachment. Investigation also found timing out of limits.

13 November 2013: Maneto distributor block bush worn allowing timng gear teeth to slip and put the timing approximately 180 degrees out. See attachments for photographs.

02 November 2013: LH magneto distributor block failed allowing magneto to retard sufficiently for engine to stop.

23 September 2013: Gear bearing in distributor block was found loose following an uncommanded engine stop on takeoff. Installation of a new distributor block and gear corrected the fault.

08 July 2013: LH magneto distributor block bushing loose causing gears to demesh.

19 June 2013: Magneto distributor block bushing loose resulting in timing problems

17 September 2012: LH magneto distributor block loose allowing distributor gear to jump teeth. Suspect bushing incorrectly installed at manufacture. See attachment for photograph.

02 March 2010: Magneto distributor block bearing dislodged causing misalignment of the distributor gear and affecting engine timing. See attachment for photograph.

23 July 2007: LH and RH magneto points defective. Points out of adjustment and timing moved.

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Granted, not all of these instances resulted in engine failures or rough running, however, the SDR's indicate the potential for such problems, should the issue not have been found and corrected.

KRviator said:

....
American pilot would expect to experience such a phenomenon and be expected to react accordingly. Commentary here suggests this may not be the case, and if this is indeed true, I would encourage a mag-check to be incorporated as part of your IA's following engine roughness or failure and be practiced as such, at the earliest opportunity. As I said earlier, it was part of the spam-can checklists I was trained under and that is going back close to 20 years, and it is there for a reason.

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This certainly affects US pilots too. Here just one NTSB report with two fatalities:

https://www.aopa.org/asf//ntsb/narrative.cfm?ackey=1&evid=20050815X01247

This is also thought as part of the emergency checklist at least by my flight instructor and AOPA points it out too:

https://www.aopa.org/news-and-media/all-news/2002/january/flight-training-magazine/the-magneto-check

So not just a problem on the other side of the world.... .

Oliver

Toobuilder said:

Please define an "automotive ignition" so that we have context. Are you discussing something from the 1960's or today? In the 60's you had a true stand alone system: Distributor, amplifier, coil... Today, with the ECU handling many functions, receiving signals from many sensors, its hard to segregate an "ignition system". You can certainly buy aftermarket coils and fat spark plug wires just like in the old days, but a "system"? Please define.

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Current ODBII ignitions is what I'm talking about Mike.

Toobuilder said:

Please cite actual failure rates "caused" by the use of "Multi component systems". Not what "could" happen, but what actual experience shows "does" happen.

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You can use the search function as well as I can.

Toobuilder said:

Compare that to the engineering challenge of cramming all that stuff into one box to satisfy a marketing niche and see where that gets you? Would you like to compare the history of "magnet misalignment " with Ross' product line? How about "lost timing events"?

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Show me one failure that has resulted from "Cramming all that stuff into one box" when properly installed.

Toobuilder said:

I'll grant P-mag the benefit of the doubt that their issues are largely resolved (with frequent, repetitive inspections), but we all know that that has been a long, uphill battle - a battle LARGELY the result of the marketing decision to package it all together - But there is no way you can pound the drum that a "distributed" system is inherently less reliable. No way. To do so flies in the face of logic and absolutely overwhelming evidence to the contrary.

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More connectors mean more places for vibration to work on.

Yes, the P-mags had some teething problems, most, if not all, of which are behind us. With thousands in use around the world, they are a proven ignition.

Toobuilder said:

It's time to put that bogey man to rest.

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I agree!

KRviator said:

No problems, Google "Magneto losing timing lycoming" and it is the 2nd from the bottom. ...

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Last year I spoke with an FAA representative regarding certifying new ignitions.

I asked the gentleman if it would be possible to certify a traditional magneto today. His response was that there is no way to certify a magneto to today's reliability standards.

N941WR said:

Yes, the P-mags had some teething problems, most, if not all, of which are behind us. With thousands in use around the world, they are a proven ignition.

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Yet, are the only ignition systems for aircraft out there with a 100 hour manufacturer recommended inspection interval. Doesn't seem to be a lot of confidence in what they've done. No change in the last 5 years as far as I'm aware. Why haven't they extended the inspection interval if they are so reliable? Not even close to a standard mag.

KRviator said:

As you can see, PMags are not alone in the lost-timing issue and I dislike the fact that at least two qualified pilots do not understand basic magneto operation enough to understand they too suffer from timing issues - and they can be a relatively common occurrence too - that can affect engine operation, instead trying to point the finger at PMag as being the only possible culprit in this regard.

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The specific cases you have raised are typically magneto timing "adjustment problems" of 4-5 degrees. Of course everyone knows that Magneto timing can drift with component wear. That's why we check magneto timing at every annual and recondition them (hopefully) at 500 hours. But the 500-hour major maintenance is frequently neglected, and it's not unusual to see an engine reach TBO without the mags ever having been removed. The fact that mags can continue to function in the face of such neglect is a testament to their inherent reliability.

What we're talking about with PMAGs is something completely different. We're talking about a condition where the timing can advance suddenly and without any warning to such an extreme degree that it causes the engine to quit (or suffer damage).

We need to see this issue in perspective. I'm guessing that there might be at least 400,000 conventional magnetos in service today in GA just in the United States. And yet engine failure caused by a properly maintained magneto suddenly (and without any warning) becoming wildly advanced is virtually unheard of.

Now compare that to the PMAG of which there may be no more than a few thousand in service and yet with a well known history of incidents related directly to extreme timing loss.

Maybe the PMAG is now beyond its loss-of-timing issues. I certainly hope so. I see that many PMAG owners claim that V40 has solved the problem. But I've heard that claim before many times over the last 10 years. It also puzzles me as to why, if V40 is the ultimate solution to the timing problem, it is not a mandatory revision. I'm not sure what that says.

N941WR said:

?..Show me one failure that has resulted from "Cramming all that stuff into one box" when properly installed...

Click to expand...

Seriously? Did you just in one fell swoop blame every documented P-mag failure on improper installation? This is the same product thar prides itself on "ease" of installation, right?

You're a smart guy. You have developed and brought to market your own product. Though we understand your product owes its very existence to the shortcomings of the P-mag ignition, I'm not about to believe that you actually think the engineering required to accurately and reliably time a spark event is difficult. Hall effect sensors have been around a very long time. They are proven to be stone axe reliable - and hanging them on the crank and block/case has been used reliably for millions and millions of hours in rain, dirt, chemicals, heat and vibration without fail. So why then did P-mag have such issues with their own application when the rest of the motorsports world does not? It's because they took the "hard way" to force a non optimal engineering solution in exchange for favor in the market as an "easy to install" option. To their credit, many have bought in to this concept (including me) and their outstanding (in my experience) customer service has kept them around long enough to gain market share. Good for them, but that's of little consequence to those who have not realized the dream of trouble free ignition performance.

More connectors mean more places for vibration to work on.

Click to expand...

Ok, but Ice Cream has no bones

Both are meaningless statements.

The real answer is a connector either meets requirements of the operating environment, or it does not. And it is abundantly clear that the weatherproof, locking, strain relieved connectors common in the current automotive world are more than up to the the task. Billions of hours of use illustrate this in spades. You can not invent a problem that has already been solved. Try again.

...Besides, do you really want to bring up connectors in light of the cheeseball stuff P-mag uses?

Toobuilder said:

...Besides, do you really want to bring up connectors in light of the cheeseball stuff P-mag uses?

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This one point is what kept me on the fence for a long time, wanting a P-Mag for its advances over a Slick, and not wanting a P-Mag because the designers made a terrible choice in electrical connectors. Eventually the desire to save fuel won out.

Had Ross's CPI not had such an ugly green control box I likely would have gone with CPI as my ignition of choice, but there was no way I was going to have a green monster in my cockpit!

When it comes time for our impulse-coupled Slick to be replaced, Ross's CPI-2 might well get the nod. I've got a spot where I can mount the controller on a mechanism which would allow it to be stowed most of the time and swung out into view only those times when its needed. And I've got an essential bus with its own battery so who knows when a CPI might make its way into our airplane.

Captain Avgas said:

The specific cases you have raised are typically magneto timing "adjustment problems" of 4-5 degrees.

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Most true, but certainly not all, and certainly not 'only 4-5*'. 1 in July 2013, 1 in September 2013, two in November 2013, with engine failures. Several close by in 2014 losing timing 'within a few hours of flight' - not just over the course of their annual or 500-hourly inspections...

What we're talking about with PMAGs is something completely different. We're talking about a condition where the timing can advance suddenly and without any warning to such an extreme degree that it causes the engine to quit (or suffer damage).

Click to expand...

See above. EFATO due timing changes can, and has been repeatedly caused by timing drift of magnetos.

We need to see this issue in perspective. I'm guessing that there might be at least 400,000 conventional magnetos in service today in GA just in the United States. And yet engine failure caused by a properly maintained magneto suddenly (and without any warning) becoming wildly advanced is virtually unheard of.

Click to expand...

So why are they being reported in Australia, but it is 'virtually unheard of' in the US? Much as CAsA and ASA would like to think so, aviation down here is not that different to anywhere else.

Now compare that to the PMAG of which there may be no more than a few thousand in service and yet with a well known history of incidents related directly to extreme timing loss.

Maybe the PMAG is now beyond its loss-of-timing issues. I certainly hope so. I see that many PMAG owners claim that V40 has solved the problem. But I've heard that claim before many times over the last 10 years. It also puzzles me as to why, if V40 is the ultimate solution to the timing problem, it is not a mandatory revision. I'm not sure what that says.

Click to expand...

How many instances of timing loss occured after V40? That is the question and the answer is sadly lacking data. Emagair may know for sure, but AIUI, there have not been any engine failures relating to timing divergence since V40 was released. As to why it is not mandatory? Who''s to say?

Mags fail too.

There, issue settled in just three words. Another public service

Come on guys, steer it back over there to the magenta line....

DanH said:

Mags fail too.

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This thread has seen some enthusiastic opinions expressed but to date it has been reasonably civilised and some interesting information has emerged. So let's keep it that way.

I think that one of the problems in assessing the reliability of experimental ignition systems is the tendency for non-disclosure of actual failures. This is certainly true of the manufacturers of the systems. Try to get some failure data from EMAG or LightSpeed and you will come up against a stonewall.

So we on VansAirforce are largely left with forming opinions on the reliability of Experimental electronic ignitions largely based on forum reports from disgruntled users.

The question that therefore needs to be asked is whether actual builders/pilots are prepared to make those disclosures on a public forum. My guess is that, in the main, they are not. And there is a logical reason for that. Does it make sense to bag Brad or Klaus's products in public when they are the only people that you can turn to to support your installation with maintenance and spare parts. I don't think so.

That leads me to believe that the reports of failures that we get are only a minor percentage of the real problems that arise with these systems. In other words the track record of these products is probably worse than you think.

And I don't think that this problem off non-disclosure applies to just experimental ignition systems. I think it probably applies in respect of all complex solid state experimental devices (e.g. EFISs) produced by essentially very small companies to whom the end user is totally dependent for ongoing support.

So I believe that there is a very large disincentive for users to complain publicly about their experimental ignitions when they have problems. On the lesser side it might damage relations with a party upon whom they rely. On the more serious side too much bad press might actually affect sales of the product leading to collapse of what is probably a very small and financially brittle company resulting in installed ignition systems being orphaned.

Some of the emotion centers around the timing failures, as they can be very inconvenient at times when we are expecting a reliable airplane. As mentioned, the same failure phenomenon applies to many other things on the airplane besides the ignition systems. That's why it is good to have a different backup and not put all of the proverbial eggs in one basket.

Sure we have a single engine airplane when talking about the RV's, but there are ways to eliminate some of the risk---- mechanical and electric fuel pumps, one mag and one electronic ignition (NOT dual electronic ignitions), dual alternators, regular maintenance, etc.

For EFIS's, I'm one who believes that the backup should be of a different manufacturer and protected as best as possible from an aircraft electrical problem. No sense frying everything when the alternator fails with over voltage.

Most likely everything about our airplanes could fail at some time. The idea is to minimize the risk while taking advantage of increases in performance. Otherwise we would just stay at home and watch TV.

Pretty soon, the electronic ignitions are going to rank up there with the primer wars.

Vic

Captain Avgas said:

This thread has seen some enthusiastic opinions expressed but to date it has been reasonably civilised and some interesting information has emerged. So let's keep it that way.

I think that one of the problems in assessing the reliability of experimental ignition systems is the tendency for non-disclosure of actual failures. This is certainly true of the manufacturers of the systems. Try to get some failure data from EMAG or LightSpeed and you will come up against a stonewall.

So we on VansAirforce are largely left with forming opinions on the reliability of Experimental electronic ignitions largely based on forum reports from disgruntled users.

The question that therefore needs to be asked is whether actual builders/pilots are prepared to make those disclosures on a public forum. My guess is that, in the main, they are not. And there is a logical reason for that. Does it make sense to bag Brad or Klaus's products in public when they are the only people that you can turn to to support your installation with maintenance and spare parts. I don't think so.

That leads me to believe that the reports of failures that we get are only a minor percentage of the real problems that arise with these systems. In other words the track record of these products is probably worse than you think.

And I don't think that this problem off non-disclosure applies to just experimental ignition systems. I think it probably applies in respect of all complex solid state experimental devices (e.g. EFISs) produced by essentially very small companies to whom the end user is totally dependent for ongoing support.

So I believe that there is a very large disincentive for users to complain publicly about their experimental ignitions when they have problems. On the lesser side it might damage relations with a party upon whom they rely. On the more serious side too much bad press might actually affect sales of the product leading to collapse of what is probably a very small and financially brittle company resulting in installed ignition systems being orphaned.

Click to expand...

My impression is that you are more likely to see a public complaint from someone that has an issue than a positive post by someone who has not. Many complain online before even contacting the manufacturer for assistance. The flip side seems to be that many that have no issues are likely never heard from unless provoked. The history here is full of examples of this behavior. You also have to wade thru all the self inflicted issues that are not product issues/failures and anyone that is in the business of selling to the masses will tell you, this is typically their #1 support issue.

Well, I'll break the mold here and publish our stats if you care to believe them. I published this (with some new additions) on another aircraft forum a while back. Note, most of our systems for aircraft, outside of military usage, are integrated fuel and ignition systems so more complex than ignition-only products. I've presented the whole history here to the best of our records and my recollections. If you're a direct SDS customer, feel free to ad any comments, negative or positive.

The stats on our electronics, compiled over the last 20+ years (reported to us or observed personally, attributed to actual electronic component failure):

550,000 + flight hours on over 1850 systems
High time ECU- 145,000 hours (bench test one)
High time fliers of our systems- 1500 hours (Rover V8), 1700 hrs (Lycoming O-360 and Subaru), 2 at 2000+ hours (Rotax 912 and Jabiru used for flight training)
High time automotive system (EM-1, circa 1994 used in 5 different cars- estimated 12,000+ hours).
ECU failures on aircraft- zero
Crank sensor failures- zero
EJ25 coil pack failures- zero
Fuel pump failures- zero (2 failed when improperly mounted)
Wiring harness failures- zero
Injector failures- 2 unconfirmed (claimed but never sent back for our inspection)
Temp sensor failures- 2 in aircraft (non-critical system failure and new fix applied 5 years ago)
MAP sensor failures- 5 in aircraft (non-critical failure, cause on 4 found to be improper mounting with vacuum port facing up- moisture ingress and these sensors were 3rd party supplied as well)
TPS failures- 2 in aircraft (1 over 20 years old, moisture ingress. Sealed design used for last 10 years)

Incidents/ Accidents

We've heard of 1 forced landing which was the result of poor wiring by the installer with an injector wire pinched to ground. Same customer, some time before had intermittent engine running, traced to a very scary wiring connection to injector power.

One V6 where the user installed an aluminum exhaust system which collapsed under the heat load and melted through the Hall sensor cable. Forced landed in a tomato field. Afterwards, we supplied with fire sleeve over the cables and now have Tefzel cables.

One plane limped around the pattern after takeoff on 3 of 4 cylinders with an apparently dead injector (low EGT and CHT indication). Landed safely. Injector was checked extensively, worked fine in testing. ECU changed out and old one sent back. No fault found in old one and it has been running perfectly in our shop car for nearly 4 months now. We suspect a wiring issue in the aircraft as no fault was found with the ECU or other components. I should mention that this aircraft has a brand X ignition system on it, not ours. This one remains a mystery.

One fatal accident locally here where I helped the TSB find that the installer had mis-wired circuits to the wrong breaker value. Breaker tripped at about 300 feet AGL, pilot tried to land back on a crossing runway, stall/spin.

We've had reports of three, 3rd party ignition drivers attached to our systems which failed from poor/cold solder joints, fortunately all on the ground. Lesson: don't attach 3rd party devices to SDS. We sent new parts to people so they could remove the defective 3rd party components and continue flying safely.

At least a dozen reports of rough running/engine shutdowns in flight. Most of these eventually linked to wrong plug wires or non- resistor plugs used or wired contrary to our recommendations. Bad grounds are the #1 cause of odd running issues. Some ECUs have been found wet inside or had flood damage at some point. Third party parts added to our electronics in several cases. All aircraft down safely although probably some soiled underwear in a couple cases.

Several ECUs sent back by customers saying they didn't work. Bench tested, installed on test engine here. Worked fine, sent back, customers later found issues with their wiring or installation.

Of course, we've had a number of people screw up wiring on installation and fry things, usually when they cut into the harness and make their own connections. Others have programmed things inappropriately, mounted magnets wrong, fuel pumps with reverse polarity, forgot power and ground connections etc.

We've had some vexing, weird issues on occasion but have eventually solved almost all of them for our customers. Almost always wiring installations.

I can think of two software screwups on release of EM-5 6 cylinder systems. Discovered prior to any engines being run in one case and a rough running issue which was not a safety concern, new boards shipped to our commercial customer. New hardware/ software sent out to 4 affected customers immediately at our expense in the second case.

We supplied some components to a vendor about 10 years ago which, through insufficient testing and rushing to meet a deadline, were causing hot running coils COP. Lesson learned, test, test, test and the design is only ready when it's ready.

Zero CPI failures in aircraft or automotive usage to date.

The bottom line, based on all this experience, is that you're unlikely to suffer a critical electronic failure with our products in your flying career if not modified in some way and are properly installed and operated as we recommend.

Of course, not all EFI/EI brands have our record of reliability and some are really quite poor from reports we get from their ex-clients who are replacing other brands with our stuff.

We encourage everyone to report their problems so we can see if there is a pattern and develop a fix. I have no problem with people reporting their problems here. We won't cut off support to you.

If you've had an issue/ failure with SDS that we haven't resolved, contact me directly or post it here. We don't have anything to hide.

We're not perfect but we try to fix anything wrong and make it right. We build on evolutionary improvements which we try to test thoroughly before product release.

Yeah... and that's why my next electronic ignition will be an SDS product. Gotta like a vendor who says it like it is.

rv6ejguy said:

...The stats on our electronics, compiled over the last 20+ years (reported to us or observed personally, attributed to actual electronic component failure):

550,000 + flight hours on over 1850 systems
High time ECU- 145,000 hours (bench test one)
High time fliers of our systems- 1500 hours (Rover V8), 1700 hrs (Lycoming O-360 and Subaru), 2 at 2000+ hours (Rotax 912 and Jabiru used for flight training)
High time automotive system (EM-1, circa 1994 used in 5 different cars- estimated 12,000+ hours).
ECU failures on aircraft- zero
Crank sensor failures- zero
EJ25 coil pack failures- zero
Fuel pump failures- zero (2 failed when improperly mounted)
Wiring harness failures- zero
Injector failures- 2 unconfirmed (claimed but never sent back for our inspection)
Temp sensor failures- 2 in aircraft (non-critical system failure and new fix applied 5 years ago)
MAP sensor failures- 5 in aircraft (non-critical failure, cause on 4 found to be improper mounting with vacuum port facing up- moisture ingress and these sensors were 3rd party supplied as well)
TPS failures- 2 in aircraft (1 over 20 years old, moisture ingress. Sealed design used for last 10 years)...

Click to expand...

An enviable track record, for sure.

Do these total fleet hours in service include the SDS units "re branded" and sold as their own?

Ross, where can I download a wiring diagram for the CPI?

Toobuilder said:

An enviable track record, for sure.

Do these total fleet hours in service include the SDS units "re branded" and sold as their own?

Click to expand...

Yes, this estimate includes re-branded ECUs which account for nearly 1/4 of the total number but not total number of flight hours since they've only been using our ECUs for about 5 years.

Of course some of these numbers like total flight time are educated estimates. We have hundreds of customers with many hundreds of hours each. The military UAV flight hours are obviously not discussed with us directly but we've heard from someone acquainted with one project saying that a couple of airframes flew over 3000 hours each and we don't know if the ECU was transferred to another engine or the airframe/ engine was lost in use at that point.

I should add that the architecture and software is very similar between the aircraft and automotive side so we get feedback/ experience from the vastly larger automotive side where we have many millions of hours of operating hours on our products.

DanH said:

Ross, where can I download a wiring diagram for the CPI?

Click to expand...

For single 4 cylinder there are 2 powers (red) and 2 grounds (black) for the controller and coil pack respectively. These wires are already installed in the connectors. One more to a 12V source for the LOP switch if fitted. One wire from controller to tach. Dirt simple.

Aero CPI manual is here: http://www.sdsefi.com/cpiaircraftmanrev23.pdf

Aero supplement here: http://www.sdsefi.com/cpiaero6x.pdf

You know folks, there is a huge amount of useful (and some not so useful - you can sort that out...) data in this thread, but very little of it has to do with "PMAG Reliability in 2017". So most of the really good info will be lost because people aren't going to be able to search for it (let's all admit that the search function is pretty basic here), and they won't look under this title to find info on SDS equipment (for instance).

And there is absolutely no way a Moderator can (or will) sort this mess out.

Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

Ironflight said:

You know folks, there is a huge amount of useful (and some not so useful - you can sort that out...) data in this thread, but very little of it has to do with "PMAG Reliability in 2017". So most of the really good info will be lost because people aren't going to be able to search for it (let's all admit that the search function is pretty basic here), and they won't look under this title to find info on SDS equipment (for instance).

And there is absolutely no way a Moderator can (or will) sort this mess out.

Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

Click to expand...

Google works just fine

"site:vansairforce.com search terms here"

Search, don't sort!

Ironflight said:

...And there is absolutely no way a Moderator can (or will) sort this mess out...

Click to expand...

I thought about attempting to do so...and I'm sure some other moderators thought about it, too. And then I decided, "No way!"

Thanks for saying this, Paul.

One debate that struck me as interesting involved the idea of "distributed components", the assertion being that wires and connectors created risk.

So, how many wires are we talking about here?

I pulled up info for SDS CPI, and P-mag plus an EI Commander, since the combination is the only way to remotely compare apples to apples in terms of operator control. (Yes, I know the relative extent of control. Let's not start that debate. This is about wire count.)





Turns out there is very little difference in how much wiring is required. Each requires two power leads, and multiple grounds. Each requires two switches. Total wire count is similar.

Directly addressing physical distribution, the only truly separate critical component is the Hall effect trigger for the CPI. It seems to be pre-wired, requiring only that the installer plug pins into the box connector after running the cable through the firewall, so install risk is minimal.

Both systems have separate coils. The P-mag merely stacks a Ford coil on top of the aluminum body, complete with external wiring.

Ironflight said:

...Think about that folks - if you have presented good, new information here - think about going and starting a new thread. Or it is all lost for posterity.

Click to expand...

Fear not Paul, I have a feeling we will get to do this dance again. Fortunately there is plenty of unambiguous data in Ross’ one post to keep future debates on the straight and narrow. I’m sure several of us will be mining that one as required.

DanH said:

One debate that struck me as interesting involved the idea of "distributed components", the assertion being that wires and connectors created risk.

So, how many wires are we talking about here?

I pulled up info for SDS CPI, and P-mag plus an EI Commander, since the combination is the only way to remotely compare apples to apples in terms of operator control. (Yes, I know the relative extent of control. Let's not start that debate. This is about wire count.)





Turns out there is very little difference in how much wiring is required. Each requires two power leads, and multiple grounds. Each requires two switches. Total wire count is similar.

Directly addressing physical distribution, the only truly separate critical component is the Hall effect trigger for the CPI. It seems to be pre-wired, requiring only that the installer plug pins into the box connector after running the cable through the firewall, so install risk is minimal.

Both systems have separate coils. The P-mag merely stacks a Ford coil on top of the aluminum body, complete with external wiring.

Click to expand...

Dan, as always, you bring in good logic; however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing. (Unless the failure is in a plug wire.)

How many wires can fail in a Distributed system before it stops producing sparks?

Captain Avgas said:

So we on VansAirforce are largely left with forming opinions on the reliability of Experimental electronic ignitions largely based on forum reports from disgruntled users.

Click to expand...

...many of which are deleted by mods, especially when the report discusses a failure of a forum advertiser's product.

Brantel said:

My impression is that you are more likely to see a public complaint from someone that has an issue than someone who has not.

Click to expand...

Why would someone who has not had an issue have any cause to complain? We know what you mean though. Thing is, especially regarding a certain vendor's products, there actually are lots of threads heaping praise, whereas many (dare I say most?) threads and posts lodging complaints are actively deleted. Conversely, I don't believe I've ever seen a single "compliment" thread deleted. Expecting to search the archives and gather any meaningful data based solely on the number of threads discussing actual failures vs praise is folly.

Huge thanks to Ross for openly discussing the data! If I ever get the nerve to try another electronic ignition after my scare, it'll be one of his units.

N941WR said:

however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing. (Unless the failure is in a plug wire.)

Click to expand...

Is this entirely true, considering the apparently critical external wire connection to engine ground?

N941WR said:

Dan, as always, you bring in good logic; however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing...

Click to expand...

Do the sparks keep flowing when the coil wires (primary side) fail?

(No need to answer Bill, we know the answer)